1921} Smith: The Biology of the Chrysopide 33 
few apparently making no effort to spin. If the larve are 
disturbed while spinning, they frequently fail to spin further 
or many spin a mat of silk upon which to transform. Larve 
have repeatedly passed through the pupal stage outside of a 
cocoon and one specimen wintered without this protection. 
The cocoons are usually placed near the feeding habitat, 
i. e., the tree inhabiting species, spin their cocoons on the under 
side of leaves or under bark. In the case of C. oculata it is 
believed that they generally spin their cocoons just under the 
loose earth on the ground. Cocoons of this species are not 
often found on plants in the field. The trash carriers use their 
packet as a kind of foundation or starting point for their cocoon. 
It adheres to one side of the finished cocoon. 
The main facts concerning the spinning of the cocoon have 
been noted by several writers, but some interesting details 
have been overlooked. The larva first forms a framework by 
attaching the viscid silk thread to whatever supports are near. 
It requires an hour or more to complete the foundation, depend- 
ing on how much time has been wasted seeking places to attach 
the thread. The larva shifts its position frequently so that the 
cocoon soon assumes a spherical shape. The spinning pattern 
during the formation of the greater part of the cocoon is a 
rather constant triangular design. The larva shifts each time 
a little to one side of a true circle, so that the wall of the cocoon 
is of approximately uniform thickness throughout. As the 
larva turns in its cramped quarters, the dorsal and lateral setz 
are broken off and are spun into the cocoon structure. The 
triangles of the spinning pattern grow smaller and the move- 
ments of the larva become slower. The final spinning appears 
to be a general plastering over of the inner wall of the cocoon. 
This is effected by a copious silk secretion being spread by the 
last segment of the abdomen. The cocoons are completed in 
most cases in about 24 hours, some requiring a little more time, 
a few finish in less time. 
Especial effort was made to observe the manner of emergence 
from the cocoon, but with only partial success. It is believed 
that the circular lid through which the pupa emerges, tears in 
that peculiar manner as the result of the spinning pattern, and 
that it is torn by internal pressure exerted by the pupa. The 
writer is not positive whether the large pupal mandibles assist 
in starting the tearing at emergence; in his opinion it is possible 
